Editing Simvastatin (section)

==Adverse effects==
Common side effects (>1% incidence) may include indigestion and eczema. There is evidence to suggest that rare side effects such as joint pain, memory loss, and muscle cramps are more likely to occur in patients who take higher doses of simvastatin.<ref name="Zocor PI" /> Cholestatic hepatitis, hepatic cirrhosis, [[rhabdomyolysis]] (destruction of muscles and blockade of renal system), and myositis have been reported in patients receiving the drug chronically.<ref>{{cite book |vauthors=Baselt R |title=Disposition of Toxic Drugs and Chemicals in Man |edition=8th |publisher=Biomedical Publications |location=Foster City, CA |date=2008 |pages=1431–3 }}</ref> Serious allergic reactions to simvastatin are rare.<ref name=Rxlist>{{cite web |title=Zocor |url=http://www.rxlist.com/zocor-drug/consumer-side-effects-precautions.htm|publisher=RxList |access-date=1 December 2012 |date=14 November 2012 |url-status=dead |archive-url=https://web.archive.org/web/20121104105217/http://www.rxlist.com/zocor-drug/consumer-side-effects-precautions.htm |archive-date=4 November 2012}}</ref>

A type of [[DNA]] variant known as a [[single nucleotide polymorphism]] (SNP) may help predict individuals prone to developing [[myopathy]] when taking simvastatin; a study ultimately including 32,000 patients concluded the carriers of one or two risk [[allele]]s of a particular SNP, rs4149056,<ref>{{Cite web|url=https://www.snpedia.com/index.php?title=Rs4149056|archiveurl=https://web.archive.org/web/20090111132256/http://www.snpedia.com/index.php?title=Rs4149056|url-status=dead |title=rs4149056 - SNPedia|archivedate=11 January 2009|website=www.snpedia.com}}</ref> were at a five-fold or 16-fold increased risk, respectively.<ref>{{cite journal | vauthors = Link E, Parish S, Armitage J, Bowman L, Heath S, Matsuda F, Gut I, Lathrop M, Collins R | display-authors = 6 | title = SLCO1B1 variants and statin-induced myopathy--a genomewide study | journal = The New England Journal of Medicine | volume = 359 | issue = 8 | pages = 789–99 | date = August 2008 | pmid = 18650507 | doi = 10.1056/NEJMoa0801936 | doi-access = free }}</ref> In 2012, the Clinical Pharmacogenetics Implementation Consortium has released guidelines regarding the use of rs4149056 genotype in guiding dosing of simvastatin<ref>{{cite journal | vauthors = Ramsey LB, Johnson SG, Caudle KE, Haidar CE, Voora D, Wilke RA, Maxwell WD, McLeod HL, Krauss RM, Roden DM, Feng Q, Cooper-DeHoff RM, Gong L, Klein TE, Wadelius M, Niemi M | display-authors = 6 | title = The clinical pharmacogenetics implementation consortium guideline for SLCO1B1 and simvastatin-induced myopathy: 2014 update | journal = Clinical Pharmacology and Therapeutics | volume = 96 | issue = 4 | pages = 423–8 | date = October 2014 | pmid = 24918167 | pmc = 4169720 | doi = 10.1038/clpt.2014.125 }}</ref> and updated the guideline in 2014.<ref>{{cite journal | vauthors = Wilke RA, Ramsey LB, Johnson SG, Maxwell WD, McLeod HL, Voora D, Krauss RM, Roden DM, Feng Q, Cooper-Dehoff RM, Gong L, Klein TE, Wadelius M, Niemi M | display-authors = 6 | title = The clinical pharmacogenomics implementation consortium: CPIC guideline for SLCO1B1 and simvastatin-induced myopathy | journal = Clinical Pharmacology and Therapeutics | volume = 92 | issue = 1 | pages = 112–7 | date = July 2012 | pmid = 22617227 | pmc = 3384438 | doi = 10.1038/clpt.2012.57 }}</ref>

In March 2012, the U.S. [[Food and Drug Administration]] (FDA) updated its guidance for statin users to address reports of memory loss, liver damage, increased blood sugar, development of [[type 2 diabetes]], and muscle injury.<ref>{{cite web|title=FDA Expands Advice on Statin Risks|url=https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm293330.htm|publisher=U.S. [[Food and Drug Administration]] (FDA)|access-date=12 July 2012|url-status=unfit|archive-url=https://web.archive.org/web/20120629162246/https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm293330.htm|archive-date=29 June 2012}}</ref> The new guidance indicates:
* FDA has found that liver injury associated with statin use is rare but can occur.{{cn|date=January 2025}}
* The reports about memory loss, forgetfulness, and confusion span all statin products and all age groups. The FDA says these experiences are rare, but that those affected often report feeling "fuzzy" or unfocused in their thinking.{{cn|date=January 2025}}
* A small increased risk of raised blood sugar levels and the development of type 2 diabetes have been reported with the use of statins.  A 2010 published meta-analysis found for every 255 patients taking a statin for 4 years, one additional case of diabetes would occur whilst preventing 5.4 major coronary events.<ref>{{cite journal | vauthors = Sattar N, Preiss D, Murray HM, Welsh P, Buckley BM, de Craen AJ, Seshasai SR, McMurray JJ, Freeman DJ, Jukema JW, Macfarlane PW, Packard CJ, Stott DJ, Westendorp RG, Shepherd J, Davis BR, Pressel SL, Marchioli R, Marfisi RM, Maggioni AP, Tavazzi L, Tognoni G, Kjekshus J, Pedersen TR, Cook TJ, Gotto AM, Clearfield MB, Downs JR, Nakamura H, Ohashi Y, Mizuno K, Ray KK, Ford I | display-authors = 6 | title = Statins and risk of incident diabetes: a collaborative meta-analysis of randomised statin trials | language = English | journal = Lancet | volume = 375 | issue = 9716 | pages = 735–42 | date = February 2010 | pmid = 20167359 | doi = 10.1016/S0140-6736(09)61965-6 | s2cid = 11544414 }}</ref>
* Some drugs interact with statins in a way that increases the risk of muscle injury called myopathy, characterized by unexplained muscle weakness or pain.{{cn|date=January 2025}}

On 19 March 2010, the FDA issued another statement regarding simvastatin, saying it increases the risk of muscle injury (myopathy) when taken at high doses or at lower doses in combination with other drugs.<ref name="fda.gov">{{cite web |url=https://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm204882.htm |title=FDA Drug Safety Communication: Ongoing safety review of high-dose Zocor (simvastatin) and increased risk of muscle injury|date=19 March 2010|access-date=21 March 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100320111330/https://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm204882.htm |archive-date=20 March 2010 |publisher=U.S. [[Food and Drug Administration]] (FDA)}}</ref> The highest dose rate causes muscle damage in 610 of every 10,000 people in contrast to a lower dose, which causes muscle damage in eight of 10,000 people.<ref name=twsJunI>{{cite news | vauthors = Sternberg S |title = Simvastatin can damage muscles in high doses |work = [[USA Today]] |quote = The cholesterol-lowering drug simvastatin can cause severe muscle damage and should not be prescribed in high doses to patients who have taken it for less than a year or in any dose to people taking certain drugs, health officials said Tuesday. . . . Research has shown that the highest dose of simvastatin, 80 milligrams, causes muscle damage in 61 of every 1,000 patients, far higher than the eight-per-10,000 rate in patients taking a 40-milligram dose, Rosenblatt says. |date = 9 June 2011 |url = http://yourlife.usatoday.com/health/medical/story/2011/06/Simvastatin-can-damage-muscles-in-high-doses/48208588/1 |access-date = 9 June 2011 |url-status = dead |archive-url = https://web.archive.org/web/20110611043816/http://yourlife.usatoday.com/health/medical/story/2011/06/Simvastatin-can-damage-muscles-in-high-doses/48208588/1 |archive-date = 11 June 2011 }}</ref> The FDA warning, released again on 8 June 2011, suggested that high-dose "simvastatin should be used only in patients who have been taking this dose for 12 months or more without evidence of muscle injury" and that it "should not be started in new patients, including patients already taking lower doses of the drug."<ref name=FDAJun2011 />